This disclosure relates in general to networking and, more specifically, but not by way of limitation, to networking over controlled long delay links.
Network access via satellite link has many speed limitations imposed by the long time delay of the link. Since the bulk of the Internet is composed of landline and short wireless links, communication delay has traditionally been associated with either slow or congested links. This bias has translated into standard protocols that create typical delays for satellite users that are much longer than just the sum of the typical landline delay plus the inherent satellite transmission delay.
Since one of the main uses for the Internet is web browsing, much effort has been done to speed up the loading of web pages over long delay links. For example, “A Smart Internet Caching System” Dias, et al., Internet Society INET 1996, is directed toward the acceleration of web browsing by the use of an intelligent agent at a distant (in terms of transmission time) gateway. One function of this agent is to observe base pages as they come from web servers and pre-fetch any in-line files (for example, images) that are referred to in the base page. These files are then pushed across the long delay link to be cached for immediate access by the user upon request. Although this method can be employed on satellite links, it has serious limitations because of the overhead involved and the possibility of pushing unneeded information over the long delay link. For example, if a user is loading the home page for a shopping server, the home page may be customized to that user. In this case, the link resources would be wasted loading generic in-line elements that do not apply to the current user. As well, locally running web applications such as Java are not well served by a pre-fetching technique.